I have used these inexpensive locks on my concert guitars for years and never had any problem. They are especially effective on my dreadnaught Guilds and Ovations. I have bought several and given them to friends who have asked what I use and none of us have had any problems with them. I like the fact that I can put them on and take them off easily and can use them on different guitars. To date I have not had any fail or break, but I don't do "stunts" with my guitars, either. (Not knocking those who do – just making the point that I don't and that might make a difference.)

I use a Planet Waves strap with built-in locks for my Fender LIII and Guild DeArmond and Planet Waves Quick Release Attachment (and these locks) for my Guild 12-string and Guild D-25, since they don't have front buttons. I haven't had any problems with any of these items in the years that I have been using them.

I bought these for my brand new Rolland Ax Synth because it seemed that they were the only option for my keytar. They did actually fit, but they came apart several times while we installed them, and then they actually popped off when I was playing and the keytar fell. Thanks alot, Dunlop. I won't be spending any money on your products any time soon.

Love the prospect of NOT replacing my strap buttons, but really NOT satisfied with the product.

The opening is too small to fit over the buttons on my American PRS or my American Strat.

I did manage to get them in place on an old bass guitar, but they came apart in the process (not a really big deal, because they just pop back together).

Once on, they seem like they would keep the strap locked (hence the two-star rating), but they are a little too big & stick out beyond the end of the strap--not a big deal on the tail of the guitar, but a nuisance up by the horns.

This strap lock is pretty decent especially if you're really cheap like me. I used it with my Epiphone Les Paul Studio, which is pretty heavy. It lasted than a longer time than I expected, but it eventually snapped in two pieces within a year. Overall its decent, but I wouldn't feel safe for guitar flips